In combat, planetary structures appear in space on the same tactical "map" as ships do - the planet is visible in the background as a low-resolution static image. Yes, this includes missile bases and ground batteries.
Neither planetary bombardment nor ground invasions have any animations, like MoO2 used to have.
I'm currently waging war against the Sakkra who acted fairly reasonably - I colonized a planet next to one of their systems despite them demanding I wouldn't do so. Two turns later they demanded X amount of credits, I refused. Few turns after that, their fleet opened the war with a surprise assault.